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Re: My '98 GU 4.2D

Posted: 22 Mar 2017 10:04
by Dustin
End of day 1 progress.
Intake and exhaust system stripped.
I love seeing old parts coming off, because it means new goes on :lol:

Re: My '98 GU 4.2D

Posted: 22 Mar 2017 10:10
by Dustin
A quick size comparison of old exhaust vs. new :thumbup:
I asked a friend at EP Muffler / Tuffex to do me a favor on a good price for 76mm diameter mild steel exhaust with no boxes... R6500 :thumbdown:
Making it all myself !
So far I've bought the 76mm pipe, flanges, gaskets and 250mm flex all for under R1200.
I made my own dump pipe for the turbo.

Re: My '98 GU 4.2D

Posted: 22 Mar 2017 10:38
by Dustin
Made rubbings of all the faces of the turbo, traced in AutoCAD and had 10mm mild steel flanges laser cut.
R225 for laser cutting all the flanges.

Bought short radius butt weld bends from my local steel supplier.
The outer and inner diameters vary a bit from the mild steel 76mm pipe i'm using, but not by enough to make a significant restriction in gas flow.
76mm bends were R48 each
63mm bends were R37 each (used for wastegate port and intake manifold inlet so I can turn it 90degrees to get the silicone hose to work on the top mount intercooler)

Checked the orientation of the flange on the turbo mock mounted on the manifold, also checked the direction of the exhaust to miss the chassis rail and brake lines.
Tack welded 76mm bend to flange and shaped the 63mm bend with an angle grinder using a cutting disc and flap sanding wheel.
Made sure of the fit and flared the edges out where needed to fit the 76mm bend.
Marked the profile of the 63mm bend on the 76mm bend and allowed for wall thickness offset.
Got stuck in with a cutting disc for the main cuts, then drilled out the perimeter and finally smoothed out the cut with a pneumatic die grinder with a rotary file bit.
Welded up and hey presto, I have a custom 3" dump pipe for about R150 ! :thumbup:
I'll weld in a separator plate once I have the turbo back from the guys making the gaskets.

I also turned down some M8 cap screws to make sure they clear the pipe :biggrin:

Re: My '98 GU 4.2D

Posted: 22 Mar 2017 11:24
by ricster
Dustin, that looks bee-friggin-utiful !!!! well done !!!

Dont want to be a stick in the mud, but did you check that that dump pipe will fit between the fire wall ( and various piping ) and the exhaust side of the turbo. I know that some turbos are slightly longer than others. I know for example the Borg Warner turbo is a VERY tight fit and has a very tight radius dump pipe. I'm not sure what turbo you are going to use, but just check .... WWW WWW

BTW mine is a Chinese rip off of a Garret I think, and mine also has a very tight radius dump

Re: My '98 GU 4.2D

Posted: 22 Mar 2017 11:47
by Rudolph
Nice very nice! :salute:

Re: My '98 GU 4.2D

Posted: 22 Mar 2017 11:50
by Dustin
Haha... 2 steps ahead of you there bud :lol:
I've got roughly 165mm from turbo to firewall.
My custom job only eats 110mm :thumbup:
Plenty of space for a heat shield behind the dump pipe.

I set it up with a 25 degree offset towards the block and then made up a lobster bend (segmented) in the 76mm pipe to return it to vertical so I can miss the chassis and piping.
The 45 degree or shallower bends I'll also make up using the lobster method.
The rear axle is where all the fun will be with the bends :confused:
I just have to take small steps and go one day at a time :biggrin:

Re: My '98 GU 4.2D

Posted: 22 Mar 2017 11:54
by Dustin
Just waiting for the manifold and turbo to get back from the gasket guys this Friday.
I hate waiting :mad:
I'll hopefully have the bulk fitted up this weekend if all goes to plan.
Then it's just waiting for the pump, Madman and making up all the little things to got on.

Hopefully I can get the whole thing back together by the first week of April.

Re: My '98 GU 4.2D

Posted: 22 Mar 2017 12:07
by Bre
Great stuff :woo:

Re: My '98 GU 4.2D

Posted: 22 Mar 2017 12:19
by ricster
Excellent , excellent Dustin !!.... Remember to drill and tap a hole for the EGT probe in the exhaust mani before fitting it... :thumbup: :thumbup:

Re: My '98 GU 4.2D

Posted: 22 Mar 2017 14:06
by Dustin
The turbo I'm using is a Hitachi HT18.
The reason I chose the HT18 is it tops out efficiency at 0.9bar of which I will only need max 0.8bar to hit my 130kW goal, and it was cheap :rolling:
Basically the UD40 trucks use the TD42ti motors, so the manifold and turbo fit the TD42 perfectly.

The turbo I sourced from a fellow Patroller for R3000.
It came off of a running Patrol that replaced the turbo for more horses.

The manifold I hunted like a mad man all over the country until I found it at a truck breaking yard in JHB for R2000.
Thanks to Tinus for going to check it out and picking it up for me :thumbup:

I had planned on doing a rebuild on the turbo simply because I don't plan on pulling it at a later stage to do the same thing, so while it's off just do it anyway.
Turned out to be a wise decision as I found the oil seals were poked, but not enough to notice on the running vehicle.

To send the turbo in to rebuild and balance would have been around R4500, so once again I did it myself :lol:
I sourced a rebuild kit from Turbos Online in CT for R550.
I had to 're purpose' an old pair of needle nose pliers into cir clip pliers to get down into the turbo core and remove the 4 retainer clips of the journal bearings.

I Googled and Youtubed rebuilding turbos until it became a disorder :rolling:
It's actually a really easy job :mytwocents:

Steps are as follows :

- Remove clamp bolts on compressor and impeller housings.
- With a scribe or sharp implement score an alignment line on the core and housings to keep the orientation to put back on the vehicle.
- A slight tapping with a rubber mallet will pop the housings loose.
- Clamp the impeller nut (exhaust side) into a vice as it is welded to the impeller and shaft.
- Remove the nut from the shaft on the compressor wheel side.
- With a scribe or sharp implement score an alignment line on top of the compressor wheel and on the shaft to make sure you will be able to line them up on reassembly to keep the balancing correct.
- Remove the compressor wheel carefully ! The veins are very brittle.
- Lightly tap the reverse side of the backing plate with a rubber mallet to pop it off of the core.
- Clamp the core in the vice and lightly encourage the shaft out with a rubber mallet. The whole shaft & impeller wheel will drop through the core.
- Remove journal bearings from the core and replace, along with all the other seals.
- The critical seals are the compressor seal on the backing plate and the piston oil seal on the shaft at the impeller wheel.
- To replace the piston oil seal, spread the gap gently with the correct tool (not a pliers or screwdriver :lol: ) and drop down onto the groove.
- The open gap of the piston oil seal MUST be on top directly inline with the turbo oil feed. If it's not, it will leak and the turbo will smoke.
- The shaft and impeller wheel assembly will click into place (remember the piston oil seal gap alignment).
- Reassemble the backing plate and compressor wheel and line up the marks you made for balancing.
- Assemble clamps and bolts on the housings.
Easy peezy ! :blonde:

I found out the hard way that I had the wrong rebuild kit for my HT18 :doh:
They had sent me a 2nd generation HT18 kit and mine ( Murphy's law) was a 1st generation turbo.
The only difference was mine had a carbon seal on the backing plate and the 2nd gen has a dynamic seal.
The carbon seal is a very scarce item to find, but Donovan from Turbos Online sourced it chop, chop and it was in my hands in no time with no charge.

I had to machine my own tool to seat the carbon seal into the backing plate, because the carbon seal is very brittle and you have to apply pressure on the steel casing.
So off to the lathe and I machined a custom tool that would fit in my drill press chuck.
I used the drill press as an arbor press to keep the force evenly distributed on the casing.

I took the core to The Turbo Shop and they balanced and tuned the core for R370.
They said the core was perfect and only a tiny tune up was required to get the max efficiency out of it :thumbup:

So... from R4500 having it done by a company, I rebuilt it myself for R920.
R3580 saved :blonde:

Turbo - R3000
Manifold - R2000
Turbo rebuild - R920
Total - 5920